Projectile equipped with a safety device



March 13, 1956 E. w. BRANDT PROJECTILE EQUIPPED WITH A SAFETY DEVICE 2 Sheets-Sheet 1 Filed Jan. 16, 1953 uwwiw A I EMBRANDT IN VE NTOR ATTORNEYS March 13, 1956 E. w. BRANDT PROJECTILE EQUIPPED WITH A SAFETY DEVICE 2 Sheets-Sheet 2 Filed Jan. 16, 1953 EMBRA DT INVENTOR ATTORNEY! United States 2,737,888 PROJECTILE EQUIPPED- wirrr A SAFETY DEVICE Edgar William Brandt, Geneva, Switzerland, assignor to Anstalt fiir die Entwicklung von Erfindungen und gewerblichen Anwendungen Energa, Vaduz, Liechtenstein, a holding company This invention relates to means adapted to ensure perfect safety in artillery projectiles, and more particularly in hollow-charge projectiles, both during transport and handling and, when fired, over a certain distance forward of the muzzle of the weapon;

More particularly the invention relates to a projectile of the type comprising inside a casing, a hollow explosive charge the cavity of which is covered with a metal cap open at its apex, and means of transmitting fire through said cap from a front fuze to a rear detonator.

The projectile of the present invention is characterized in that, before the firing of the shot, the detonator is housed in the inoperative position inside a safety cage contiguous to the charge carrier base of the projectile and is adapted, after the firing of the shot, to take up its operative position in the explosive charge at the rear of the apex of the cap.

The housing of the detonator in the safety position in a cage separate from the part of the projectile containing the charge offers full safety to the operators.

If the head fuze should fire prematurely as the result of a fall, the transmission of fire to the detonator is ineffective to explode the charge, since the detonator is remote and separate from the latter.

The invention is advantageously applicable to projectiles stabilised by an empenna-ge, since in that case the safety cage may at the same time constitute a fin carrier.

According to a modification of the invention, the detonator is enclosed, in the inoperative position, in an intermediate chamber, from which it is separated by a peripheral space, said chamber being itself housed in the safety cage.

Thus the explosion of the detonator, in the inoperative position, is damped by the walls of the intermediate chamber, and the products of the explosion cannot under any circumstances disrupt the safety chamber.

It is obvious that if the safety cage were to explode while the projectile was still in the gun barrel, the propulsive gases could penetrate inside the projectile and communicate the fire to the explosive charge.

Furthermore, the premature explosion of the detonator during transport and handling or during storage cannot communicate fire to the propulsive charge contained in the case of the projectile.

According to a modification of the invention, the detonator is held in the inoperative position by an inertia member traversed by a conduit adapted to transmit the fire from the head fuze to the detonator.

Said inertia member may cooperate in known manner with a system of balls adapted, by displacement, to free the inertia member and at the same time the detonator, which can then assume the operative position.

The aforesaid inertia members serves as a secondary safety device and is adapted to be plastically deformed under the effect of the explosion of the detonator, so as to obturate, similarly to a valve, the passage passing through it, thus preventing access of the gases to the interior of the cap and the transmission of fire from the detonator, in the inoperative position to the explosive charge.

In order to enable the invention to be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example various embodiments thereof, and in which:

Figure 1 shows a side elevation partly in section of a finned projectile provided with the device of the present invention;

Figure 2 is an axial section on a larger scale of the safety device of Fig. 1;

Figures 3, 4 and 5 illustrate a modification and show the functioning of the safety device respectively before, during and after the firing of the shot; and

Figures 6 and 7 illustrate another modification of a structural detail of the safety device of the invention.

The projectile shown in Figure 1, is of the hollow charge type and 'has a head fuze 1, an ogival point 2, a charge carrier body 3, a double charge 4, 5 hollowed out to provide an axial cavity or passageway, and a metal cap 6 covering the cavity of the charge 4. An internally hollowed fin carrier 7' is mounted on the base 5a of the charge carrier body 3, and movablefins 8 constituting a folding empennage are articulated at the rear end of the fin carrier 7, as described and claimed in the specification of the co-pending application No. 316,016.

The projectile is'packed inside a case 9, the base of which comprises a cartridge carrier 10.

The safety device 11 is housed inside the cage which is formed by the fin carrier 7.

As shown in Figure 2, said safety device comprises a movable detonator 12 which, in-the' inoperative'position, is locked by balls 13 inside a detonator carrier 14 against the action of a spring 15.

According to the preferred embodiment, the detonator 12 is coupled with a relay 16, the jacket 17 of which is supported by a bearing surface 18 onthe balls 13, which in turn are retained in the locking position by means of a ring 19. The latter is adapted to move back on the firing of the shot against the action of a spring 20, thus freeing the balls 13, which are withdrawn into a housing provided for the purpose.

After firing and on cessation of the positive acceleration, the ring 19 is retained by an elastic ring 21 in a groove 22 made in the periphery thereof (see Figure 5).

In Figures 3 and 5, the safety device is provided with a supplementary jacket 23 constituting an intermediate chamber inside the safety cage 7 It is moreover advantageous to provide a secondary safety device in the form of an obturator 24 interposed in the fire passage from the head fuze 1 to the detonator 12. The obturator 24 is retained in its housing by a ball 25 preventing it from escaping forwards and by a spring 26 which prevents it from moving backwards during transport and handling. Finally, the obturator 24 is connected through the medium of the spring 26 with a valve 27 resting on an inner lip 27'.

In the embodiment shown in Figures 6 and 7 the relay is replaced by an inertia member 1711 deformable under pressure and retained in position by the balls 13 acting on an annular bearing surface 18a on said inertia member. The latter is traversed by a conduit adapted to transmit fire to the detonator 12.

It should be noted that the inertia member 17a has a relatively great wall thickness in relation to its diameter, so that the premature explosion of the detonator The hereindescribed safety device operates as follows:

On the firing of the shot, the ring 19 moves back, comaressing the spring 20 on to its seating, while the elastic 'ing 21 penetrates into the corresponding-groove 22, thus 'reeing the balls 13. At the same time, the obturator 24 noves back against the action of the spring 26 (Figure 4), 1nd the ball 25 escapes and is received in the concave art 24a of the obturator.

On the cessation of the positive acceleration (Figure :he detonator 12 coupled with the relay 16 is carried :owards the front and assumes the operative position, While the obturator 24 and the valve 27 are withdrawn nto the cavity of the hollow charge. At this moment :he transmission of fire from the head fuze to the deto- 1211101 12, through the medium of the relay 16, effects the explosion of the charge 4, 5. On the other hand, in the .noperative position, the detonator 12 is not able to transnit fire to the explosive charge, being insulated from the .atter in its housing.

Premature explosion of the detonator 12 in the inoperative position is damped in the peripheral jacket surrounding the same, so that the safety cage formed by the fin carrier of the projectile remains intact.

What I claim is:

l. A projectile comprising a jacket open at the front and rear, a percussion fuse in the head of the jacket, an explosive charge inside said jacket and having an axial passageway, a metal cap lining the forward part of said passageway and being open at its rear end to transmit fire from the fuse, a housing mounted on the rear open end of said jacket, said housing having a peripherally spaced supplementary jacket, a detonator, holding means for retaining said detonator in said housing rearwardly of said charge, inertia-actuated means for releasing said detonator and permitting it to move forwardly into the an explosive charge inside said jacket and having an axial passage-way, a metal cap lining the forward part ofsaid passageway and being open at its rear end to transmit fire from'the fuze, a housing mounted onthe rear open end of said jacket, a detonator, and displaceable means for holding said detonator in said housing rearwardly of said charge, and inertia-actuated means for releasing said dctonator, and permitting it to move forwardly into the passageway behind the cap to receive fire from the fuze, said displaceable means comprising a sliding inertia member through which runs a longitudinal conduit, said member being adapted to be plastical'ly deformed by the explosion of said d'etonator in such a manner as to obturate said conduit passing therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 672,827 Gathmann Apr. 23, 1901 734,697 Gathmann July 28, 1903 1,321,407 Taylor Nov. 11, 1919 1,327,600 Lukend Jan. 6, 1920 1,944,780 Brandt Jan. 23,1934 2,441,388 Blackinton et al May 11, 1948 2,521,739 Meister Sept. 12, 1950 2,697,400 "Liljegren Dec. 21, 1954' FOREIGN PATENTS 614,320 Great Britain Dec. 14, 1948 625,333 Great Britain June 27, 1949 

